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Najman, M.N.; Kasrai, M.; Bancroft, G.M.

doi:10.1023/a:1022650516272

Cited by 81 publications

(27 citation statements)

References 20 publications

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“…Main peak a and broad peak c align closely with those of FeS, spectrum M. This compound performs as an EP additive, and it has been shown before, that under EP conditions the film is mainly composed of FeS [31]. On the other hand, under AW conditions, spectrum G shows, in addition to FeS, broad peaks c and d corresponding to S(IV) and S(VI) oxidation states.…”

Section: Tribofilmssupporting

confidence: 70%

Study of interaction of EP and AW additives with dispersants using XANES

et al. 2005

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The chemical interaction of two kinds of dispersants (bis-succinimide dispersant and borated bis-succinimide dispersant) with four kinds of antiwear (AW) and extreme pressure (EP) additives (zinc dialkyldithiophosphate, dialkyldithiophosphate ester, diphenylphosphate ester and dialkyldithiocarbamate) has been investigated under different contact pressures. The chemical compositions of the tribofilms have been studied by B, N, P and S X-ray absorption near edge structure (XANES) spectroscopy. The N K-edge XANES analysis has been used to follow the reaction pathway of amine and imide functional groups in the dispersants and their interactions with EP and AW additives. It has been found that AW additives react with amine to form amine phosphate at low load. However, at high load, there is a good evidence for the formation of a nitrate phase in the tribofilms, the first direct observation of oxidative dispersant loss in the rubbing contact. On the other hand, EP additives behave differently and in general are less reactive. The B K-edge XANES has been employed to follow the interaction of borated dispersant with the EP and AW additive. In general, boron originally in the trigonal coordination, is converted to a tetrahedral coordination form in the process of tribofilm formation.

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Section: Tribofilmssupporting

confidence: 70%

Study of interaction of EP and AW additives with dispersants using XANES

et al. 2005

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“…These peaks are similar in position to the three peaks for a typical alkyl sulphide. [17] Peaks d and e, near 172.5 and 180.7 eV, respectively, show the presence of some sulphate on the film surface, consistent with the above XPS results. This indicates that the outer surface (about 5 nm depth) of the tribofilm is mainly composed of an alkyl sulfide, along with a little amount of sulphate.…”

Section: Thermal Stabilitysupporting

confidence: 88%

“…The details about the friction and wear tests on the Plint machine were provided elsewhere. [17,18] The additive was added to the base stock, at a mass fraction of 1.2%. The thermo-oxidative films (thermal films) were prepared through immersion of the steel coupon in a glass bottle containing the oil solution (the base oil containing 1.2 wt% synthesized additive), for a specific length of time (approximately 6 h) at 150…”

Section: Preparation Of the Tribofilms For Xanes Analysesmentioning

confidence: 99%

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The tribological behaviours of dithiocarbamate‐triazine derivatives as additives in mineral oil

et al. 2008

Surface & Interface Analysis

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Ashless and non-phosphorus hydroxyl-containing dithiocarbamate-triazine compounds,2,4,6-tri[N,N-di-i-octyldithiocarmate-(2 -hydroxyl)-propionylthio]-1,3,5-s-triazine (LDION) were prepared and their tribological behaviour as additives in mineral oil were evaluated using a four-ball tester. Thermal degradation tests were conducted to identify their thermal stabilities using a thermo-gravimetric analyser. The worn surfaces were investigated by X-ray photoelectron spectroscopy (XPS) and X-ray absorption near edge structure (XANES) spectroscopy. The results indicate that the additive LDION possesses high thermal stabilities and good load-carrying capacities. Moreover, it has good anti-wear property at all test concentration and under all test loads. The results of XPS and XANES analyses illustrate that the prepared compounds as additives in mineral oil forms a protective film containing oxidised compounds and organic nitrogen-containing compounds and inorganic sulfate on the metal surface during sliding process.

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“…It has been demonstrated previously that chlorinated hydrocarbons function by reactively forming a FeCl 2 film [17][18][19] at the high temperatures (>1000 K [20]) encountered at the solid-solid interface during EP applications. Sulfur-containing additives decompose to form FeS under EP conditions, and FeS 2 at the lower temperatures found in less severe AW applications [21]. Phosphorus-containing EP additives often consist of phosphite or phosphate esters with formulae P(OR) 3 or O@P(OR) 3 respectively, where R is a hydrocarbon species or hydrogen [12][13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Reaction of tributyl phosphate with oxidized iron: surface chemistry and tribological significance

et al. 2005

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The chemistry of tributyl phosphate on Fe 3 O 4 was studied in ultrahigh vacuum using temperature-programmed desorption (TPD) and Auger spectroscopy. A portion of the tributyl phosphate desorbs intact with an activation energy of $120 kJ/mol. The remainder decomposes either by PAO bond scission to deposit surface butoxy species or appears to dehydrogenate desorbing C 2 or C 3 compounds and depositing hydrogen and carbon on the surface. The resulting hydrogen reacts either with the oxide to desorb water or with butoxy species yielding 1-butanol. The remaining butoxy species are stable up to $600 K where they decompose to desorb butanal via hydride elimination where again the hydrogen reacts with butoxy species to form 1-butanol or with the oxide to form water. The carbon deposited onto the surface further reduces the oxide to desorb as CO above $750 K, although a small amount of carbon is detected on the surface using Auger spectroscopy. Substantially larger amounts of carbon are deposited onto the surface when Fe 3 O 4 is exposed to tributyl phosphate at 300 K, where an Auger depth profile reveals that the carbon is located at the surface while the PO x species formed by tributyl phosphate decomposition diffuse rapidly into the oxide layer, leading to a film structure in which graphitic carbon is deposited onto a phosphorus-containing oxide layer.

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Untitled

Cited by 81 publications

References 20 publications

Study of interaction of EP and AW additives with dispersants using XANES

Study of interaction of EP and AW additives with dispersants using XANES

The tribological behaviours of dithiocarbamate‐triazine derivatives as additives in mineral oil

Reaction of tributyl phosphate with oxidized iron: surface chemistry and tribological significance

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